38 C.F.R. § 20.1408

In the case of a motion under this subpart to revise a final Board decision in a simultaneously contested claim, as that term is used in Rule 3(l) (§ 20.3(l) of this part), a copy of such motion shall, to the extent practicable, be sent to all other contesting parties. Other parties have a period of 30 days from the date of mailing of the copy of the motion to file a brief or argument in answer. The date of mailing of the copy will be presumed to be the same as the date of the letter which accompanies the copy. Notices in simultaneously contested claims will be forwarded to the last address of record of the parties concerned and such action will constitute sufficient evidence of notice.